Make bitmask 'and' operators return a result code

When 'and'ing two bitmasks (where 'andnot' is a variation on it), some
cases want to know whether the result is the empty set or not.  In
particular, the TLB IPI sending code wants to do cpumask operations and
determine if there are any CPU's left in the final set.

So this just makes the bitmask (and cpumask) functions return a boolean
for whether the result has any bits set.

Cc: stable@kernel.org (2.6.30, needed by TLB shootdown fix)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 2878811c61346f09520ffdc086742c77943e91ea..756d78b8c1c5e52195fc4b0db951c883c1a07122 100644 (file)
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -94,13 +94,13 @@ extern void __bitmap_shift_right(unsigned long *dst,
                         const unsigned long *src, int shift, int bits);
 extern void __bitmap_shift_left(unsigned long *dst,
                         const unsigned long *src, int shift, int bits);
-extern void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
                        const unsigned long *bitmap2, int bits);
 extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
                        const unsigned long *bitmap2, int bits);
 extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
                        const unsigned long *bitmap2, int bits);
-extern void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
                        const unsigned long *bitmap2, int bits);
 extern int __bitmap_intersects(const unsigned long *bitmap1,
                        const unsigned long *bitmap2, int bits);
@@ -171,13 +171,12 @@ static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
        }
 }
 
-static inline void bitmap_and(unsigned long *dst, const unsigned long *src1,
+static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
                        const unsigned long *src2, int nbits)
 {
        if (small_const_nbits(nbits))
-               *dst = *src1 & *src2;
-       else
-               __bitmap_and(dst, src1, src2, nbits);
+               return (*dst = *src1 & *src2) != 0;
+       return __bitmap_and(dst, src1, src2, nbits);
 }
 
 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
@@ -198,13 +197,12 @@ static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
                __bitmap_xor(dst, src1, src2, nbits);
 }
 
-static inline void bitmap_andnot(unsigned long *dst, const unsigned long *src1,
+static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
                        const unsigned long *src2, int nbits)
 {
        if (small_const_nbits(nbits))
-               *dst = *src1 & ~(*src2);
-       else
-               __bitmap_andnot(dst, src1, src2, nbits);
+               return (*dst = *src1 & ~(*src2)) != 0;
+       return __bitmap_andnot(dst, src1, src2, nbits);
 }
 
 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index c5ac87ca7bc647d32caef606c9c26ab0bb606090..796df12091b7687a450d26e57c4acf6ecc15b34d 100644 (file)
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -43,10 +43,10 @@
  * int cpu_isset(cpu, mask)            true iff bit 'cpu' set in mask
  * int cpu_test_and_set(cpu, mask)     test and set bit 'cpu' in mask
  *
- * void cpus_and(dst, src1, src2)      dst = src1 & src2  [intersection]
+ * int cpus_and(dst, src1, src2)       dst = src1 & src2  [intersection]
  * void cpus_or(dst, src1, src2)       dst = src1 | src2  [union]
  * void cpus_xor(dst, src1, src2)      dst = src1 ^ src2
- * void cpus_andnot(dst, src1, src2)   dst = src1 & ~src2
+ * int cpus_andnot(dst, src1, src2)    dst = src1 & ~src2
  * void cpus_complement(dst, src)      dst = ~src
  *
  * int cpus_equal(mask1, mask2)                Does mask1 == mask2?
@@ -179,10 +179,10 @@ static inline int __cpu_test_and_set(int cpu, cpumask_t *addr)
 }
 
 #define cpus_and(dst, src1, src2) __cpus_and(&(dst), &(src1), &(src2), NR_CPUS)
-static inline void __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
+static inline int __cpus_and(cpumask_t *dstp, const cpumask_t *src1p,
                                        const cpumask_t *src2p, int nbits)
 {
-       bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
+       return bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
 }
 
 #define cpus_or(dst, src1, src2) __cpus_or(&(dst), &(src1), &(src2), NR_CPUS)
@@ -201,10 +201,10 @@ static inline void __cpus_xor(cpumask_t *dstp, const cpumask_t *src1p,
 
 #define cpus_andnot(dst, src1, src2) \
                                __cpus_andnot(&(dst), &(src1), &(src2), NR_CPUS)
-static inline void __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
+static inline int __cpus_andnot(cpumask_t *dstp, const cpumask_t *src1p,
                                        const cpumask_t *src2p, int nbits)
 {
-       bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
+       return bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
 }
 
 #define cpus_complement(dst, src) __cpus_complement(&(dst), &(src), NR_CPUS)
@@ -738,11 +738,11 @@ static inline void cpumask_clear(struct cpumask *dstp)
  * @src1p: the first input
  * @src2p: the second input
  */
-static inline void cpumask_and(struct cpumask *dstp,
+static inline int cpumask_and(struct cpumask *dstp,
                               const struct cpumask *src1p,
                               const struct cpumask *src2p)
 {
-       bitmap_and(cpumask_bits(dstp), cpumask_bits(src1p),
+       return bitmap_and(cpumask_bits(dstp), cpumask_bits(src1p),
                                       cpumask_bits(src2p), nr_cpumask_bits);
 }
 
@@ -779,11 +779,11 @@ static inline void cpumask_xor(struct cpumask *dstp,
  * @src1p: the first input
  * @src2p: the second input
  */
-static inline void cpumask_andnot(struct cpumask *dstp,
+static inline int cpumask_andnot(struct cpumask *dstp,
                                  const struct cpumask *src1p,
                                  const struct cpumask *src2p)
 {
-       bitmap_andnot(cpumask_bits(dstp), cpumask_bits(src1p),
+       return bitmap_andnot(cpumask_bits(dstp), cpumask_bits(src1p),
                                          cpumask_bits(src2p), nr_cpumask_bits);
 }
 

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 35a1f7ff414988d86c6c081d7bbf3671733a15d6..702565821c9976fb4588dac793d84008bf93b229 100644 (file)
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -179,14 +179,16 @@ void __bitmap_shift_left(unsigned long *dst,
 }
 EXPORT_SYMBOL(__bitmap_shift_left);
 
-void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
                                const unsigned long *bitmap2, int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
+       unsigned long result = 0;
 
        for (k = 0; k < nr; k++)
-               dst[k] = bitmap1[k] & bitmap2[k];
+               result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+       return result != 0;
 }
 EXPORT_SYMBOL(__bitmap_and);
 
@@ -212,14 +214,16 @@ void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 }
 EXPORT_SYMBOL(__bitmap_xor);
 
-void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
                                const unsigned long *bitmap2, int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
+       unsigned long result = 0;
 
        for (k = 0; k < nr; k++)
-               dst[k] = bitmap1[k] & ~bitmap2[k];
+               result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
+       return result != 0;
 }
 EXPORT_SYMBOL(__bitmap_andnot);